Heretofore, there is a method of manufacturing a stator core by laminating steel sheets produced by press-punching and then the stator core mounted thereon with a coil is molded of resin by injection molding.
On the other hand, there is also another method of manufacturing a stator core by assembling a plurality of split cores on each of which a coil is mounted. In this case of using the split cores, they are assembled integrally by use of a shrink fitting ring.
JP2006-180698A discloses a method of manufacturing a split stator by molding resin on a split core. This publication discloses a technique of producing an insulator integral with the split core in such a way that a cavity for insulator is provided around a teeth part of the split core between the split core and a molding die, and then resin containing fibrous inorganic reinforcing materials is injected into the cavity.